The overall objectives of the total project concern the elucidation of parallel pathways in determinng psychophysical and evoked potential responses to contrast modulated grating patterns. Our studies established that pattern adaptation makes the detection of modulation independent of the mean contrast level at several spatial frequencies near the peak of the human contrast sensitivity curve. Pattern adaptation also shifts a predominant first harmonic EP repsonse to contrast modulation to stronger second harmonic domination. Second harmonic EP components may be the response of human visual pathways which are resilient to pattern adaptation. Our investigation in patients with M.S. show that there is no concurrence between VEP latency changes and contrast sensitivity losses to the identical pattern. In view of our findings concerning parallel pathways in the human, it is relevant that we found contrast sensitivity losses in patients with glaucoma predominantly at low spatial frequencies around 8 Hertz modulation rate.